Method and device using high interior pressure to reshape structural section

ABSTRACT

A method using high interior pressure to reshape structural section of continuously bounded overall cross-section, whereby the overall cross-section can be provided with extra walls or chambers and a stopper is forced radially against each end of the piece.  
     The object is to reduce wear on the stopper while ensuring that any walls or chambers in addition to its overall cross section will buckle or bulge only at their ends.  
     Either any walls ( 2  &amp;  3 ) that partition the chambers ( 4, 5,  &amp;  6 ) and any independent wall ( 7 ) are provided with slots ( 17 ) at the ends of the piece that parallel the inner surface ( 18 ) and outer surface of the piece or the stopper ( 8 ) itself is provided with grooves ( 19 ) adjacent to and matching the shape of the walls.

[0001] The present present invention relates first, to a method usinghigh interior pressure to reshape structural section as recited in thepreamble to Claim 1, and second, to a device as recited in the preambleto Claim 5 for carrying out the method.

[0002] The structural section being reshaped using high internalpressure may be tubing as disclosed in German 3 923 358 A1 and in U.S.Pat. No. 4,414,834 A. Pieces with a non-circular cross-section, however,can also be reshaped. Such material is usually extruded.

[0003] To ensure unobjectionable fluid tightness, a stopper is forcedradially against each end of the structural section. The end of thepiece rests against an edge of the stopper, creating a seal. To reducewear on the stoppers as much as possible, the seal-creating edge is madeof a wear resistant material and is forced against the interior surfaceof the section subject to relatively high pressure.

[0004] It would also be desirable to similarly use high interiorpressure to reshape pieces with extra walls or chambers projecting intoor out of their overall cross-section. There is, however, a drawback tosuch a procedure in that the walls or chambers tend to deform axiallyalong the piece, allowing the edges to buckle or bulge out axiallyundefined. It is of course possible to counteract this tendency bymaking the edges of a softer material. This approach, however, increaseswear on the edges.

[0005] The object of the present invention is accordingly a method ofand a device for using high interior pressure to reshape structuralsection with walls or chambers that project into or out of its overallcross-section, whereby the stoppers are subjected to low wear andwhereby the extra walls or chambers will buckle or bulge out only attheir ends.

[0006] This object is attained by the characteristics recited in Claims1 and 5. Practical and advanced embodiments are addressed in Claims 2through 4 and 6 through 9.

[0007] The major advantage of the present invention is that complexstructural section with extra walls or chambers can be reshaped usinghigh interior pressure, decreasing the cost of manufacture. Since thesection is reshaped only slightly at the ends, they will need to betrimmed only slightly if at all as the material is further processed.

[0008] One embodiment of the present invention will now be specifiedwith reference to the accompanying drawing, wherein

[0009]FIG. 1 is a view of one end of a length of extruded structuralsection with several walls,

[0010]FIG. 2 is a larger-scale view of detail II in FIG. 1,

[0011]FIG. 3 illustrates a stopper sealing off the end illustrated inFIG. 1, and

[0012]FIG. 4 is a larger-scale view of detail IV in FIG. 3.

[0013]FIG. 1 depicts a length of typical extruded structural sectionthat is to be reshaped using high interior pressure. The extrusion has acontinuously bounded cross-section 1 partitioned by two walls 2 and 3into three chambers 4, 5, and 6. Finally, the section is provided withan independent wall 7 that extends out of cross-section 1.

[0014] While it is being reshaped and still inside the reshaping tool,the ends of the piece are sealed by stoppers 8 forced radially againstthem. Each stopper 8 is provided with a seal-creating edge 9 establishedon the surface of a gasket 10 that rests against the stopper. Each edge9 accordingly fits tight into the structural section. Each stopper 8 isprovided with aligners 11, 12, and 13 that more or less fit intochambers 4, 5, and 6, which they enter into as stopper 8 is advancedtoward the piece. Partitioning walls 2 and 3 and overall cross-section 1are accordingly secured radially, the overall piece being introducedagainst and correctly positioned in relation to each stopper 8. Gasket10 and aligners 11, 12, and 13 can now attach the schematicallyillustrated connectors 14, 15, and 16 to stopper 8. Connectors 14, 15,and 16 can also convey the fluid that provides the reshaping pressure.

[0015] To ensure a well controlled buckling or bulging out by walls 2,3, and 7, they are provided with slots 17 more or less paralleling theinner surface 18 or outer surface of cross-section 1. The slot 17 in theillustrated example is very near inner surface 18. These slots arepreferably produced by an appropriately shaped bit on stopper 8 as thestoppers are brought together.

[0016]FIG. 4 illustrates an alternative or additional embodiment of thepresent invention. Gasket 10 is in this embodiment provided with grooves19 extendng along the walls 2 and 3 that partition cross section 1.Grooves 19 allow partitioning walls 2 and 3 to stretch axially withoutbuckling or bulging as the section is reshaped. Since the independentwall 7 that extends out of cross-section 1 does not rest against stopper8, the measures addressing this wall in the foregoing will obviously notbe necessary. What is on the other hand essential is that grooves 19 donot extend all the way to edge 9, providing the overall structuralsection with a well defined continuous seal.

List of Parts

[0017]1. overall cross-section

[0018]2. partitioning wall

[0019]3. partitioning wall

[0020]4. chamber

[0021]5. chamber

[0022]6. chamber

[0023]7. independent wall

[0024]8. stopper

[0025]9. seal-creating edge

[0026]10. gasket

[0027]11. aligner

[0028]12. aligner

[0029]13. aligner

[0030]14. connector

[0031]15. connector

[0032]16. connector

[0033]17. slot

[0034]18. inner surface

[0035]19. groove

1. Method using high interior pressure to reshape structural section ofcontinuously bounded overall cross-section, whereby a stopper is forcedradially against each end of the piece, characterized in that when, inaddition to its overall cross section (1), the piece is provided withone or more extra walls (2, 3, & 7) or chambers (4, 5, & 6), the stopper(8) will seal the structural section only at its continuous boundary. 2.Method as in claim 1, characterized in that the independent wall (7) andthe partitioning walls (2 & 3) are provided with slots (17) that projectmore or less out of the inner surface (18) and the outer surface of theoverall cross-section (1).
 3. Method as in claim 2, characterized inthat the slots (17) are less than 1 cm deep.
 4. Method as in claim 2 or3, characterized, when the structural section has several chambers (4,5, & 6), by additioal slots (17) at the intersections between andbranches off of the partitioning walls (7).
 5. Device for using highinterior pressure to reshape structural section of continuously boundedoverall cross section, whereby a stopper is forced radially against eachend of the piece, characterized in that when, in addition to its overallcross-section (1), the piece is provided with one or more extra walls(2, 3, & 7) or chambers (4, 5, & 6), the stopper (8) will seal thestructural section only at its continuous boundary.
 6. Device as inclaim 5, characterized in that the stopper (8) is provided with grooves(19) that match the shape of, and merge with, the extra walls (2, 3, &7).
 7. Device as in claim 5, characterized in that the grooves (19)extend almost to the boundart of the overall cross-section (1). 8.Device as in claim 6 or 8, characterized in that the grooves (19) areless than 1 cm deep.
 9. Device as in one or more of claims 6 through 8,characterized, when the structural section has several chambers (4, 5, &6), by additioal grooves (19) at the intersections between and branchesoff of the partitioning walls (7).